Sports boards are generally preformed, preshaped, generally planar boards composed of a foam material with a gliding bottom surface for use on water, snow, grass, ice or other surfaces.
In particular, one type of sports board comprises a body or surf board and is employed in the water, particularly for use for surfing. Generally, body boards are formed or made of polyethylene, typically with a cross-linked polyethylene foam core, and have polyethylene foam sheets laminated to the polyethylene foam core. Body boards, when used for surfing purposes, may have a lower bottom surface composed of a polymeric film material, to provide a smooth or gliding slick finish to the lower surface of the board. This low-frictional surface creates less drag and promotes quick release from the surface on which the board is used. Generally, the lower surface of the body board has a thermoplastic polymer film, such as a cross-linked polymer, or a solid polyethylene film heat-laminated to the bottom surface. The polymer film material, so applied, may contain a thin layer of thermoplastic polymer on one side to promote the heat-laminating to the bottom surface of the board, while the other side has a glossy smooth surface. However, such film employed must be of a thickness, generally 20 mils or greater, sufficient to permit its application to the bottom surface without any wrinkling, as it is essential that the bottom surface be a smooth surface for gliding purposes.
Further, in sports boards, particularly boards used for surfing purposes, the boards should have outwardly extending side rails extending from one to the other end of the body board, optionally, and also partially around the front of the board, constituting an upper and lower side rail surface. Side rails are employed to permit a user to grasp the side rails and maneuver the board.
Sports boards may be made of a polymer material, but usually are composed of an inner core material of a lower density, and then having a higher density, closed-cell foam material, such as a polyethylene, heat-laminated to the top and bottom surface of the core foam, to form the overall preshaped, preformed sports board, and optionally outwardly extending straight or slightly arcuate side rails on the back surface of the board. Optionally, the board may also have a designed foot surface on the back, generally curved inwardly a short distance and having a flat, angular surface.
The upper and lower surfaces of the body board are generally composed of a closed-cell foam material, such as a cross-linked polyethylene foam material. The inner core foam material is generally of low density, such as two pounds psi, and the laminated upper and lower surfaces, which form the outer core, have a density of about six pounds psi. Where the sports board is employed in rugged sports pursuits, such as professional or semi-professional surfing, the board should be sufficiently stiff to maintain its planar shape with continued use.
A wide variety of sports boards, including body boards, are known. One such sports board, having a slick film surface about the entire surface, and the method of making such a sports board has been described in U.S. Pat. No. 4,850,913, issued Jul. 2, 1989, hereby incorporated by reference in its entirety. The sports board described comprises a preformed, preshaped foam core of closed-cell foam material, with a sheet of polyethylene film laminated to an outer layer sheet of polyethylene foam. The polyethylene film is laminated to all outer surfaces of the sports board, to completely cover the outer surface of the core. Such a sports board provides an outer, glossy, impervious polyethylene film surface for reducing friction and decreasing the board's ability to absorb water. The employment of a slick film surface totally covering all board surfaces is not wholly desirable, however, for all conditions and uses.
It is therefore desirable to provide for a new and improved sports board, particularly a body board used for surfing purposes, and a method for making such a board, and which method simplifies manufacturing of the board, and provides for a lower polymer film surface of reduced thickness, without the disadvantages associated thereof, and which provides a board with increased low-frictional surface only on the bottom surface and the lower side rails to provide enhanced stiffening properties. Further, the frictional top surface and top side rail surface allows for stability for the user on the board and increased ability to grasp and maneuver the board in use.